FIG. 1 illustrates a known door threshold. In FIG. 1, threshold 1 serves as a carpet divider, is located under the door, and includes at least one overhang 3 under which carpet 4 and carpet pad 6 may be run. The FIG. 1 threshold is typically made of aluminum.
Threshold 1 of FIG. 1 requires the presence of carpet tacks 5 and supports 7 therefor proximate to the overhangs 3 in order to fasten down the carpet 4 so as to prevent the carpet from slipping out from over the overhangs 3. However, if the carpet 4 wears out, or tears, tacks 5 tend to poke through the carpet and can be a hazard because they can injure feet of a person walking near the threshold.
FIG. 2 is a perspective view of a door threshold that reduces and/or eliminates the need for carpet tacks, thus representing an improvement over certain prior art systems. Thresholds of this type are disclosed in, for example, application Ser. No. 11/344,114, the entire content of which is hereby incorporated herein by reference. Threshold 10 may be of aluminum or the like. Threshold 10, on one or both sides thereof, includes upper and lower members, 12 and 14 respectively, which sandwich an end of carpet 4 therebetween. As shown in FIG. 2, carpet pad 6 may stop short of the lower member 14 so that only the carpet 4 is sandwiched between the upper and lower members 12 and 14 in certain embodiments (although this need not be the case in all embodiments). In certain embodiments, at least parts of the upper and lower members 12 and 14 are substantially parallel (i.e., parallel plus/minus about 20 degrees) to one another.
In certain embodiments, upper and/or lower member(s) 12, 14 grip or otherwise maintain the carpet 4 that is located therebetween. Thus, the need for carpet tacks proximate to the threshold is reduced and/or eliminated because the threshold itself maintains the end of the carpet in position and reduces the ease with which it may be pulled out from between members 12, 14. Overhang 12 may be flexible in certain embodiments, so as to provide a downward-directed biasing force against the carpet 4 to help maintain the end of the carpet between members 12 and 14. The threshold further allows for a variety of different carpet and/or pad thicknesses, and can maintain a slight rise above the carpet for a door sweep to seal against and yet not rub or significantly rub on the carpet when closing.
Carpeting 4 typically is glued down or stretched and held by carpet tack strips along the walls. At the door opening, the carpet cannot be glued to a pad typically. The carpet tuck feature of threshold 10 effectively grips the carpet and reduces the ease with which it may be pulled away from the threshold. The carpet will have been stretched and held at either side of the door opening.
As shown in FIG. 2, the top surface 10a of the threshold 10 includes a peak or highest elevation portion 10b. Then, the top surface 10a preferably slopes downwardly from peak 10b on both sides thereof to lower elevation portions 10c. The top surfaces of lower elevation portions 10c typically are sloped from about 5 to 60 degrees, more preferably from about 10 to 35 degrees, relative to the a top flat portion of peak lob. Moreover, as shown in FIG. 2, the bottom member or base 14 of the threshold may be divided into two separate and distinct feet 14a and 14b that are separated from one another by gap or cavity 15. Typically, the gap or cavity 15 is located under the peak portion 10a of the threshold. Feet 14a, 14b are preferably attached to the floor (or other support located over the floor) via an adhesive, screws, or the like. The door frame may be made of steel, aluminum, wood, or any other suitable material.
While the thresholds described with reference to FIG. 2 are more advantageous than certain prior art thresholds, further improvements are still possible. For example, sometimes a stock threshold, also called a transition strip, is provided to allow for separating carpet colors and/or patterns. However, such stock transition strips do not account for the many variations in wall- and frame-depth. For example, current thresholds are made to a specific depth dimension and, as such, cannot effectively address the desire to have a single stock threshold span the many variations in wall- and frame-depth. Accordingly, many thresholds do not meet certain fire codes, some of which may require a true fire separation under the door and do not allow carpet-to-carpet detailing.
A typical opening where such problems arise may be, for example, a connecting room double-door setup (e.g. in a hotel), where it is desirable to span the entire frame depth. This arrangement is depicted in FIG. 3. Briefly, two doors 20a-b are provided for closing the entry way formed by walls 24a-b. A threshold 22 is disposed between doors 20a-b. As noted above, it would be advantageous to use a stock threshold to span the entire wall- and/or frame-depth. The threshold 22 would be set under doors 20a-b and have notches 26a-d for accommodating one or more stops 28a-b. 
Thus, it will be appreciated by those skilled in the art that there exists a need in the art for an improved door threshold(s).
One aspect of certain example embodiments relates to a door threshold structure comprising a main body formed from a male foot and a female foot.
Another aspect of certain example embodiments relates to a door threshold structure comprising a main body formed from two female feet connected via a center insert. Other components are also possible in certain instances.
Still another aspect of certain example embodiments relates to a door threshold structure comprising a main body formed from two feet butt-joined to a center insert.
Yet another aspect of certain example embodiments relates to a door threshold structure comprising a main body formed from one foot joined to a riser.
Accordingly, in certain example embodiments, a door threshold structure to be at least partially located underneath at least one door when the at least one door is in a closed position, in combination with a carpet is provided. A first foot and a second foot may be configured to be connected (directly or indirectly) to form a main body of the door threshold structure. The first foot may include a protrusion formed thereon for engaging with a recession in the second foot. On at least one side of said main body there may be provided upper and lower members extending from the main body in spaced apart relation from one another so that the upper and lower members may be at least partially substantially parallel to one another. The carpet may be located adjacent to the threshold. A gap between the spaced apart upper and lower members may be configured to receive an end of said carpet.
In certain other example embodiments, a door threshold structure to be at least partially located underneath at least one door when the at least one door is in a closed position, in combination with a carpet, is provided, wherein the door threshold structure may comprise a first foot and a second foot configured to be connected via a center insert to form a main body of the door threshold structure. On at least one side of said main body there may be provided upper and lower members extending from the main body in spaced apart relation from one another so that the upper and lower members are at least partially substantially parallel to one another. The carpet may be located adjacent to the threshold. A gap between the spaced apart upper and lower members may be configured to receive an end of said carpet.
According to certain other example embodiments, a a door threshold structure to be at least partially located underneath at least one door when the at least one door is in a closed position, in combination with a carpet, is provided, and the door threshold structure may comprise a foot configured to be connected to a riser to form a main body of the door threshold structure. On one side of said main body there may be provided upper and lower members extending from the main body in spaced apart relation from one another so that the upper and lower members are at least partially substantially parallel to one another. The carpet may be located adjacent to the threshold. A gap between the spaced apart upper and lower members may be configured to receive an end of said carpet.
The upper member may be flexible and an end thereof may be biased downwardly toward an end of the bottom member in order to grip carpet located between the upper and lower members.